This invention relates to an application sharing system which enables sharing of application processing by a plurality of terminal users.
By the use of a plurality of terminals connected via a network, a plurality of terminal users can participate in a joint work such as a conference. In this event, information must be shared among the users. As one of such information sharing, sharing of application processing is known. Herein, sharing of application processing is to make a result of the application processing executed in each user's terminal be reflected at other user's terminals in real time and may simply be called application sharing.
The application sharing is classified into a centralized execution system and a decentralized or distributed processing system. In the centralized execution system, an application program runs on a particular one of the terminals which collects all inputs supplied through the respective terminals, executes the application processing, and delivers the result of processing to the respective terminals. On the other hand, in the distributed processing system, application programs of the same sort run on the respective terminals each of which collects all inputs supplied through the respective terminals, and executes the application processing. Thus, the centralized execution system requires the result of processing to be sent back to the respective terminals. This brings about an increase in communication traffic. In order to suppress the increase in communication traffic, it is preferred to use the distributed processing system with less traffic. For example, a conventional application sharing system using the distributed processing system is disclosed in Japanese Unexamined Patent Publication (JP-A) No. 6-83785 (83785/1994).
However, the conventional application sharing system using the distributed processing system is basically operated in a manner such that the application programs of the same sort are simultaneously started in the respective terminals and mutually communicate with one another to realize the application sharing. No special consideration is made about any possible change in operating condition of the application programs. It is therefore difficult to flexibly adapt to dynamic changes in working environment and to smoothly proceed with a work, as will hereinafter be described.
For example, in a certain working environment, a single user solely performs the work by the use of the application program and, at a particular time instant, another user desires to participate to jointly proceed with the work. In such circumstances, it is impossible in the conventional application sharing system to shift the application program being solely operated into a shared condition. Thus, it is impossible to change a sole work into a joint work.
On the contrary, it is assumed that a plurality of users jointly perform the work and, after a particular time instant, one of the users solely continues the work. In this event, it is impossible in the conventional application sharing system to shift the shared condition of the application program into a sole operation condition. Thus, it is impossible to change the joint work into the sole work.